Thread pulling device



1956 c. J. M. BENINK 2,730,980

THREAD PULLING DEVICE Filed Aug. 20, 1954 Fig.7

a- Fig.3

2o /6 o 21 Q 3 i 15 Ill 41 T 29 b UnitedStates Patent THREAD PULLINGDEVICE Christian Josef Marines Benink, Kaiserslautern, Germany, assignorto G. M. Pfaif A.-G., Kaiserslautern, Pfalz, Germany, a corporation ofGermany Application August 20, 1954, Serial No. 451,153 Claims priority,application Germany November 30, 1953 14 Claims. (Cl. 112-242) tended tobe restricted thereby save as pointed out in the claims.

An object of this invention is to provide at the be ginning of thesewing operation a sufficient length of thread for the first stitch, forinstance as needed in button sewing machines. The first stitch in suchmachines needs to be larger than the succeeding stitches. Therefore, inorder to have more thread for the first stitch, the thread will bepulled at the end of the preceding operation in accordance with theinvention, so that an additional length of thread is available at thestart of the succeeding operation.

A further object of the invention is to tighten th last stitch when thesewing operation is terminated preparatory for severing the thread.

Generally speaking, the invention provides for a thread pulling device,on a sewing machine with a controlled operating cycle, for instance abutton sewing machine. During the customary sewing operation the threadpasses through the pulling device in a straight path between a fixedthread tensioner and a fixed thread guide. When the sewing operation isterminated and therefore the sewing machine comes automatically to astop, the pulling device will perform a twisting movement by which thethread path will no longer be straight. By this movement there isaccomplished that additional thread from the button is tensioned; thethread is temporarily clamped by clamping means which form part of thepulling device.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description, taken inconnection with the accompanying drawings, in which:

Fig. 1 is a fragmentary perspective view of a sewing machine having athread pulling device in accordance with the invention, in the pullingposition;

Fig. 2 is a plan view of the thread pulling device, but in the sewingposition;

Fig. 3 is a sectional view taken on line 3--3 of Fig. 2; and

Fig. 4 is a perspective view of the thread pulling device viewed frombelow, some parts having been omitted for the sake of clarification.

In carrying the invention into eifect in the embodiment which has beenselected for illustration in the accompanying drawings and fordescription in this specification, and referring now particularly toFig. 1, there is provided a start switch control lever 1 of the sewingmachine to which a transfer lever 2 is permanently connected. Themovements of the switch lever 1 are trans mitted through thetransferlever 2 to a crank and 2,736,989 Patented Jan. 17, 1956 to anintermediate lever 4 which, in turn, transmit the movements to alongitudinal horizontally disposed shifting rod 6. The intermediatelever 4, which has two unequal arms, is pivoted by a screw 5 to theframe of the sewing machine. The shifting rod 6 is guided forlongitudinal movements in two bearings 7 and 8 of the machine frame. Adog 9 is connected to the shifting rod 6 by means of a screw 10. The dog9 carries a pin 11 that forms a part of a cam driver 12 (Fig. 2).

Near the frame of the machine there may be put a spool S from which thethread T is pulled. The thread T reaches the needle (not shown) by wayof a fixed thread guide member 40 after passing through a fixed threadtensioner 39. The instant pulling device is located between thetensioner 39 and the guide 40. The guide 40, tensioner 39 and thepulling device are provided on the cover 13 of the sewing machine (Fig.1).

When the sewing machine is in operation, the shifting rod 6 will be inthe position shown in Fig. 2, having been moved in directionA (Fig. l).The pulling device will assume the position shown in Fig. 2, and thethread will run in a straight stretch between the fixed guide member 40and the fixed tensioner member 39, and through the pulling device thatis located between these two fixed members.

As shown in Figs. 2 and 4, the thread pulling device comprises a threaddeflector which includes an upper disc 22 and a lower disc 16. The lowerdisc 16 has a bifurcated follower 17 that engages the cam driver 12.When the sewing operation comes to a stop the shifting rod 6 will moveautomatically in the direction of the arrow B (Fig. l) and the camdriver 12 will move the follower 17 of the disc 16. By this movement,the disc 16 is taken along with the cam driver 12, and performs afraction of a rotational movement in the direction D (Fig. 4).

A hollow tubular body 14 (Figs. 3 and 4) is disposed on the cover 13 ofthe machine, and is held thereon from below by a nut 15. The body 14serves as a center of rotation for the discs 16 and 22. A spring 21 iswound around the body 14 and has one end connected to a pin 23 which issecured to, and projects from the underside of, the disc 22 (Figs. 2 and4). The other end of the spring 21 is connected to a pin or screw 20which is secured to, and extends downwardly from, the disc 16.

The outer circumference of the disc 16 has two abutment points 18 and 19that are spaced from each other, and the pin 23 of the disc 22 projectsinto the space between the abutment points 18 and 19.

As shown in Figs. 1, 2 and 3, on the disc 22 there is provided clampingmeans 24 which comprises an upper gripping jaw 25 and a lower grippingjaw 26. The upper jaw 25 may be shorter than the lower jaw 26 for easyinsertion of the thread T. A screw 27 connects the jaws 25 and 26 to thedisc 22. One of the jaws, for instance the longer jaw 26 is movable,whereas the jaw 25 is fixed. A spacer bushing 28 is provided between thejaws 25 and 26 (Fig. 3).

As seen in Figs. 3 and 4, a pushing rod 29 is provided that passesthrough the hollow tubular body 14 and thus abuts with its upper endfrom below against the jaw 26 of the clamping means 24 (Fig. 3). Thepurpose of the pushing rod 29 is to exert at predetermined instants amomentary upward pressure onto the movable jaw 26 whereby said jaw 26makes contact with the jaw 25 to clamp the thread. The upward pressureis obtained from a nose 43 which is carried by a rotating shaft 42 andthe lower end of the pushing rod 29 rests on the surface of said shaft42 at the point of the nose 43 thereof. A retraction spring 41 isprovided that presses the rod 29 downwardly against saidsurface of theshaft 42 and acts to retract the pushing rod 29 upon release by the nose43, in order to release the jaw 26. Upon release, the jaw 26 will assumeits normal lower position, allowing a smooth passing of thethread Tbetween the jaws 25 and 26.

On the disc 22 there are provided displacing means for the thread T.Theseinclude two radial guides 39 and 31 (Figs. 1 and 2), which aredisposed at right angle to the longitudinal extension of the jaws 25 and26 of the clamping means 24. On the guides 36 and 31 there are movablyheld two plates 32 and 33 that have thread guiding means, for instanceslotted thread guiding pins 34 and 35 respectively. The adjustment ofthe plates 32 and 33 and the guides 30 and 31 is rendered possible bymeans of longitudinal slots 36 and 37 that are formed in the plates 32and 33. As shown in Fig. 2, friction generating means, such as screws 33protrude through the plates 32 and 33. In this manher, the adjustment ofthe pins 34 and 35 can be made independently of each other, according tothe desired length of thread to be pulled.

Operation Duringthe normal sewing operation of the machine (Fig. 2), thethread T which is fed from the spool S is disposed in a straight pathbetween the thread tensioner 39 through the clamping means 24 of thepulling device and the thread guide 40.

When the sewing machine stops, the control switch lever 1, the transferlever 2, the crank 3, and the intermediate lever 4 will move theshifting rod 6 in the direction of the arrow B.

, The cam driver 12 of the dog 9 which is connected to the shifting rod6 will slide in the cam follower 17 of the lower disc 16, and will turnthe disc 16 in direction D from the normal position (Fig. 2) into thethread pulling position (Fig. l). The spring 21 will be taken along bythe screw 20 of the disc 16. Accordingly, the upper disc 22 which isconnected through the pin 23 to the other end of the spring 21 will alsobe taken along and performs like the lower disc 16 the rotationalmovement in the direction of the arrow D.

If any resistance exerted by the thread surpasses the tension force ofthe spring 21, the abutment point 19 will assume the function of turningthe disc 22 by push- .ing the pin 23; the space between the abutmentpoints 18 and 19 is provided to afford a time lag during which .thespring 21 may act; only upon failure of the spring to act will the point19 take over the turning of the disc 22.

The rotational movement of the discs 16 and 22 in direction D, bringsthe slotted guides 34 and 35 to a position at an angle to the normalposition of alignment with the normally straight path of thread betweenthe thread tensioner 39 and the thread guide 40. By this movement, theguides 34 and 35 pull the thread olf the normal straight path andthereby there is accomplished that additional thread is pulled off thespool S, when the clamping means 24 is closed to grip the thread.

At that instant, the pushing rod 29 will be lifted by .the nose 43against the pressure of the spring 41. The upper end of the pushing rod29 will lift the movable lower jaw 26 of the clamping means 24 and thuswill temporarily grip the thread passing between the jaws 25 and'26.

At the same time, the last stitch will be tightened because when thethread is gripped by the clamping means 24, there occurs a tension intwo directions, namely one tensioning of thethread between the clampingmeans 24 and the spool S, and a second tensioning of the thread piecebetween the clamping means 24 and the article, for instance the buttonsewn (not shown), re-

I spectively. The latter thread tightening accomplishes another of thedesired aims of the invention, namely that the thus tensioned thread canthen easily be severed at the predetermined location.

The foregoing takes place as the sewing machine comes to a stop (Fig.I).

At the beginning of the succeeding sewing operation, the operator willmove the shifting rod 6 in the direction A and the cam driver 12 willturn the cam follower 17 in direction C. The disc 22 will, under thetension of the spring 21 be turned by the lower disc 16 in the samedirection C, and both discs 16 and 22 will assume their normal sewingposition (Fig. 2).

When the disc 16 turns in direction C to assume its normal sewingposition, any resistance in the path of the thread that becomes largerthan the tension force of the spring 21, may tend to retard or to stopthe turning of the disc 22; when this occurs, the abutment point 18 ofthe disc 16 will assume the role of turning the disc 22 by pushing thepin 23 in the direction C.

Simultaneously, the nose 43 will have passed beyond its peak position,and the upward force exerted on the pushing rod 29 by the nose 43 willcease, and the rod 29 will be retracted downwardly by the spring 41.Thereby the lower jaw 26 will be lowered and the thread T that wasclamped temporarily between the jaws 25 and 26 be released.

After the pulling device returns to its normal position (Fig. 2), theadditional thread that resulted from the previous twisting movement willbe available for the larger first stitch needed to start a new sewingoperation cycle.

Since certain changes may be made in the 'above article and differentembodiments of the invention could be made without departing from thescope thereof, it is intended that all matter contained in the abovedescription or shown in the accompanying drawing shall be interpreted asillustrative and not in a limiting sense.

Having thus described the invention, what I claim as new and desire tobe secured by Letters Patent, is as follows:

l. A thread pulling device, for use in connection with a sewing machinewith a controlled operating cycle and having automatic shifting meansand a thread guide and a thread tensioner, said device comprising, amechanism in driven connection with said shifting means and including areciprocably rotatable member, and two opposite thread guiding elementsconnected to said member, said thread having a straight path betweensaid thread tensioner and said thread guide in sewing operation andbeing suspended between said thread guiding elements, said mechanismbeing actuatable by said shifting means to turn said member and guidingelements upon termination of the sewing operation for shifting thethread from. said straight path into a path intersecting, between saidguiding elements, said straight path, at an angle thereto, and clampingmeans operable for releasably clamping said thread between said guidingelements in timed relation with the actuation of said mechanism,whereby, upon actuation of said mechanism, said member will be turnedand said clamping means will clamp the thread thereby increasing theamount of thread between said guide and tensioner.

2. A thread pulling device, for use in connection with a sewing machinewith a controlled operating cycle and having automatic shifting meansand a thread guide and a thread tensioner, the thread normallystretching in a straight path between said thread guide and said threadtensioner, said device comprising, a mechanism in driven connection withsaid shifting means and operable to turn the thread from thestraightpathbetween said thread guide and said thread tensioner into a path atan angle thereto upon termination of the sewing operaticn,'including adriving and a driven member adjacent each other and journalled forrotation about the same axis at an anglet'o said straight path, a springconnected to said members forming therebetween a resilient connectionfor transmission of rotary movement, thread displacing means adjustablyconnected to said driven member, movable clamping means connected tosaid driven member and operable to be closed for frictionally engagingthe thread and, respectively, to be opened for thread release, and apushing rodconcentric with said axis and passing through said membersand operable to close releasably the clamping means.

3. A thread pulling device as claimed in claim 2, said thread displacingmeans comprising two oppositely located slotted pins operable to moveunder the tension of said spring the thread out of its normal straightpath between said thread guide and said thread tensioner.

4. A thread pulling device as claimed in claim 2, said driven memberhaving two longitudinal grooves, said thread displacing means comprisingtwo oppositely located slotted pins being movable radially on said discand operable to move under the tension of said spring the thread out ofits normal straight path between said thread guide and said threadtensioner, a plate movable in each of the longitudinal grooves of saiddriven member, and each pin being secured to one of said plates.

5. A thread pulling device as claimed in claim 2, said driven memberhaving two longitudinal grooves, said thread displacing means comprisingtwo oppositely located slotted pins being movable radially on saiddriven member and operable to move the thread out of its nor- .malstraight path between said thread guide and said thread tensioner, aplate movable in each of the longitudinal grooves of said driven member,each pin being secured to one of said plates, and friction generatingmeans protruding through said plates for adjusting said slotted pinsindependently of each other.

6. A thread pulling device as claimed in claim 2, said clamping meanscomprising two gripping jaws, a spacer bushing connected between saidjaws, one of said gripping jaws being movably connected relative to theother jaw.

7. A thread pulling device as claimed in claim 2, said clamping meanscomprising two gripping jaws, a spacer bushing connected between saidjaws, one of said gripping jaws being movably connected relative to theother jaw, said movable gripping jaw being below, and longer than, saidfixed gripping jaw.

8. A thread pulling device as claimed in claim 2, each of said membersincluding a projection, said spring having windings concentric with saidaxis, each end of said spring being connected to the projection of amember.

9. A thread pulling device as claimed in claim 2, said driving memberhaving on its outer circumference two abutment elements spaced apartfrom each other, a pin connected to said driven member and protrudinginto the space between said abutment elements, either abutmerit elementbeing operable to engage said pin after a time lag when the force ofsaid spring fails to transmit {i rotational movement from said drivingto said driven member during said time lag for assuring turning of saiddriven member with said driving member.

10. A thread pulling device as claimed in claim 2, a hollow bodyconcentric with said axis secured on the frame of the machine andjournalling said members, said pushing rod passing through said hollowbody.

11. A thread pulling device as claimed in claim 2, said spring beingoperable to turn said driven member about said axis by being tensionedabout said axis of said driving member, said driving member having abifurcated recess forming a cam follower, a cam driver disposed in saidrecess, said cam driver being connected to said shifting means andoperable to transmit the movements thereof to turn said driving memberfor tensioning said spring to turn said driven member.

12. A thread pulling device, as claimed in claim 1, said clamping meansbeing disposed between said guiding elements and engaging in allpositions said thread and normally engaging said thread slidingly,whereby said thread passes through said clamp substantially withoutfriction and, respectively, being operable for clamping said thread toengage it frictionally to arrest it upon actuation of said mechanism.

13. A thread pulling device, for use in connection with a sewing machinehaving a controlled operating cycle and means for actuating said threadpulling device at the start and stop of the sewing cycle, said threadpulling device comprising a thread deflector including a discoscillatable about its axis and having two opposite thread guidesmovable therewith engaging said thread normally following a straightpath and operable upon turning of said disc from a rest position to movethe thread from its normal straight path into a path intersecting saidnormal straight path, said disc including clamping means operable forreleasably clamping said thread when said disc is turned from said restposition.

14. A thread pulling device, as claimed in claim 13, together with, andmeans intermediate said actuating means and said disc and including aspring. and operable to actuate said disc resiliently near the startingand stopping instants of the sewing machine, said resilient means beingoperable to be tensioned by said actuating means thereby turning saiddisc with the force of said tension.

References Cited in the file of this patent UNITED STATES PATENTS540,301 Drake June 4, 1895 1,461,428 McCann July 10, 1923 1,960,924Sailer May 29, 1934 2.300.585 McCann Nov. 3, 1942

